DE102021115429A1 - Device for blow molding containers from preforms made of thermoplastic material - Google Patents

Abstract

The invention relates to a device for blow molding containers from preforms made of thermoplastic material, which has at least one blow molding station (18), at least one blow mold (28) for molding a thermally conditioned preform inserted into the blow mold (28) by means of blowing gas and at least one fluidly communicating with the blow mold (28) connected outlet opening (30) for expanding the blowing gas used in the blow mold (28), and at least one cooling device (20) for cooling the blow molding station (18) by means of a cooling fluid, wherein the cooling device (20) comprises at least one Fluid line (32) for the cooling fluid, which is connected in fluid communication with a cooling channel system (38) of the blow mold (28), wherein the outlet opening (30) is designed to generate a cooling gas flow (40) by means of the expanded blowing gas, wherein at least one section ( 34) of the fluid line (32) is arranged in the cooling gas stream (40). The invention provides an improved device (10) for blow molding containers from preforms made of thermoplastic material, which works with higher efficiency and therefore more cost-effectively.

Description

The invention relates to a device for blow molding containers from preforms made of thermoplastic material.

When blow molding containers from preforms made of thermoplastic material, the preforms are thermally conditioned by means of a heating device for the reshaping. The thermally conditioned preforms are in blow molds i.a. stretched into containers by means of a blowing gas. The blowing gas is fed into the preforms under high pressure. After stretching, the containers still have residual heat. In order to avoid subsequent deformation of the containers, the containers are cooled in the blow molds. For this purpose, the blow molds have cooling channels through which a cooling fluid, e.g. B. cooling water is passed. To provide the cooling fluid, the cooling channels are connected to a cooling device via fluid lines, so that a closed cooling circuit is formed.

It is off to generate the cooling fluid DE 10 2017 103 438 A1 known to expand the blowing gas used for stretching into a chamber in which the fluid lines of the cooling device are also arranged. The expansion of the blowing gas cools the air in the plenum chamber, thereby also cooling the fluid lines and the fluid introduced therein.

The object of the invention is to provide an improved device for blow molding containers from preforms made of thermoplastic material, which works with higher efficiency and therefore more cost-effectively.

The object is solved by the features of the independent claims. Advantageous developments are the subject of the dependent claims and the following description.

In a device for blow molding containers from preforms made of thermoplastic material, the at least one blow station, the at least one blow mold for forming a thermally conditioned preform inserted into the blow mold by means of blowing gas and at least one outlet opening connected to the blow mold in fluid communication for expanding the used in the blow mold blowing gas, and comprises at least one cooling device for cooling the blow molding station by means of a cooling fluid, wherein the cooling device has at least one fluid line for the cooling fluid, which is fluidly connected to a cooling channel system of the blow mold, it is provided according to the invention that the outlet opening for generating a cooling gas flow by means of the expanded blowing gas is formed, wherein at least a portion of the fluid line is arranged in the cooling gas flow.

With the invention, the blowing gas flowing out of the outlet opening after the production of the container is used for cooling the cooling fluid in the fluid line. After production, the blowing gas flows out of the blow mold through the outlet opening. When flowing through the outlet opening, the blown gas is expanded adiabatically, so that the temperature of the blown gas is reduced. A cooling gas flow is thus generated from the blowing gas with the outlet opening. The cooling gas flow is directed onto at least one section of the fluid line or this section of the fluid line is arranged in the cooling gas flow. The flow of cooling gas therefore sweeps around the fluid line and a heat exchange takes place, which cools the cooling fluid flowing through the fluid line. This brings about additional cooling of the cooling fluid, with the fluid line being able to be both a supply line and a return line of the cooling device. The cooling of the cooling fluid in the fluid line improves the energy balance of the device and avoids an unnecessary introduction of cold into the surroundings of the blow molding station. Furthermore, the capacity of the cooling device can be made smaller, so that a less expensive cooling device can be used. In this way, the device can be operated with higher efficiency and thus more cost-effectively.

According to an example, the at least one portion of the fluid line can have a heat exchange element arranged in the cooling gas flow.

The cooling of the fluid line and of the cooling fluid flowing therein is further improved with the heat exchanger element. The heat exchanger element has an enlarged surface compared to the fluid line, so that the heat exchange between the cooling gas flow and the fluid line is improved.

It is also conceivable that the device can have a collection chamber for collecting the expanded blowing gas with at least one passage opening for the cooling gas flow, the outlet opening being connected to the collection chamber in fluid communication and the at least one section of the fluid line being arranged in the passage opening.

The expanded blown gas is collected in the collection chamber, so that the temperature in the collection chamber is reduced. The introduction of the blowing gas increases the pressure in the collection chamber, so that a flow of cooling gas is created through the through-opening. Because the at least one Section of the fluid line is arranged in the through hole, the entire expansion cold of the expanded blowing gas can be used to cool the cooling fluid.

In a further example, the device can have a drying air chamber with at least one drying air opening directed towards the blow mold for generating a curtain of drying air from the heated cooling gas flow, the drying air chamber being arranged downstream of the cooling gas flow in relation to the collecting chamber and being connected in fluid communication with the collecting chamber via the through-opening .

The blow mold can be dried with the dry air curtain to counteract the formation of condensation. The flow of cooling gas, which has been heated by the heat exchange with the fluid line, is introduced into the drying air chamber through the through openings. The heated flow of cooling gas is collected in the drying air chamber and directed through the drying air openings to the blow molds as a curtain of drying air. This further increases the efficiency of the device.

The device can also have, for example, at least one chamber wall that is thermally insulated.

Both the plenum and the dry air plenum may have thermally insulated chamber walls to prevent heat exchange with the plenum environment. This further increases the energy efficiency of cooling.

It is also conceivable that the at least one fluid line can be, for example, a cooling fluid supply line or a cooling fluid return line.

Preferably, the fluid line is the cooling fluid return line. The heated cooling fluid that flows from the blow mold to the cooling device is thus cooled by the cooling gas flow. The return temperature of the cooling fluid is thus reduced. There is thus a pre-cooling of the cooling fluid, so that the cooling device requires less energy to cool the cooling fluid to the desired cooling temperature for the blow mold.

However, this does not rule out the possibility that the fluid line can be the cooling fluid feed line. In this case the cooling device does not have to cool the cooling fluid to the required cooling temperature since the cooling gas flow can cause further cooling of the cooling fluid to the required cooling temperature before it is introduced into the tuyere.

A silencer, for example, can further be arranged at the outlet opening for dampening noise of the expanding blown gas.

For example, the muffler may include an alignment element for aligning the flow of cooling gas with the fluid line.

The cooling gas flow can thus flow in a directed manner against the fluid line, so that the majority of the cooling gas flow flowing out of the outlet opening sweeps over the fluid line. This further increases the cooling effect of the cooling gas flow.

Furthermore, the device can have, for example, a large number of blow molding stations, which are each connected to the cooling device in a fluid-communicating manner via at least one fluid line.

• 1 eine schematische Darstellung einer Vorrichtung zum Blasformen von Behältern aus Vorformlingen aus thermoplastischem Material; und
• 2 eine schematische Querschnittsdarstellung einer Blasstation.

The invention is described below using an exemplary embodiment with the aid of the attached drawing. Show it:

• 1 a schematic representation of an apparatus for blow molding containers from preforms made of thermoplastic material; and
• 2 a schematic cross-sectional view of a blow molding station.

The device for blow molding containers from preforms made of thermoplastic material, as described in 1 shown, denoted in its entirety by the reference numeral 10 in the following.

The device 10 can have a feed device 12 which feeds the device 10 with preforms. In one example, the preforms can be transferred to a heating section 16 of the device 10 by means of a transport wheel 14 . As they pass through the heating section 16, the preforms are thermally conditioned for later forming into containers.

After passing through the heating zone 16, the thermally conditioned preforms, e.g. B. by means of another transport wheel 14, a blow molding station 18, z. B. a blow wheel 26 are passed. In the blow molding station 18, the preforms are formed into containers in at least one blow mold 28. The blow molding station 18 can have a large number of blow molds 28 .

A cooling device 20 cools the blow molds 28 with a cooling fluid and for this purpose can be connected to the blow molds 28 via a cooling fluid supply line 22 and a cooling fluid return line 24 via the blow molding station 18 .

After forming, the containers, e.g. B. by means of another transport wheel 14, are removed from the blow molding station 18. The containers produced can further, e.g. B. by means of one or more additional transport wheels 14, an output device (not shown) are transferred to z. B. to a coating device and / or sterilization device and / or to a filling device (not shown) to be transported.

Blow molding station 18 is in 2 shown in more detail. It can have a blow wheel 26 to which at least one blow mold 28 is connected. In the blow mold 28, a preform can be stretched into a container by means of blowing gas. For this purpose, the thermally conditioned preform is placed in the blow mold 28 and expanded by means of blowing gas, among other things, so that the walls of the preform are pressed against the walls of the blow mold 28 .

After forming, the container produced still has residual heat from the thermal conditioning of the preform. In order to avoid undesired deformation of the container in the blow mold 28, the container is cooled via the blow mold 28.

For this purpose, the blow mold 28 has a cooling channel system 38 which is connected to the cooling device 20 in fluid communication via at least one fluid line 32 . For this purpose, the fluid line 32 can be in fluid-communicating connection with the cooling fluid supply line 22 and/or the cooling fluid return line 24 . For this purpose, the cooling fluid supply line 22 and/or the cooling fluid return line 24 can be connected to the blow wheel 26 with a rotary inlet 48 . The rotary inlet 48 is also connected to the cooling channel system 38 of the blow mold 28 . In this way, cooling fluid can be conducted from the cooling device 20 into the cooling channel system 38 .

Once the container has cooled sufficiently to no longer deform in the tuyere 28, the blown gas is released from the container. For this purpose, the blow molding station 18 has an outlet opening 30 which is connected to the blow mold 28 in a fluid-communicating manner.

When the pressurized blown gas exits the outlet port 30, the blown gas may flow into a plenum 42 which is at a lower pressure than the blown gas. The blown gas is therefore expanded adiabatically and cools down. A cooling gas flow 40 is produced from the cooled blowing gas. A silencer 46 can be provided at the outlet opening 30 in order to reduce the resulting noise development.

The muffler 46 can further have at least one alignment element 58 with which the cooling gas flow 40 is directed onto a section 34 of the at least one fluid line 32 .

Alternatively or additionally, the collection chamber 42 can have at least one passage opening 60 to a drying air chamber 44 , the cooling gas stream 40 flowing out of the collection chamber 42 through the passage opening 60 . Further exhaust air openings are not provided on the collecting chamber 42 so that the cooling gas flow 40 can only leave the collecting chamber 42 through the passage opening 60 .

The section 34 of the fluid line 32 can be arranged and fixed in the through opening 60 so that the cooling gas stream 40 flows around the section 34 of the fluid line 32 and a heat exchange between the cooling gas stream 40 and the section 34 of the fluid line 32 can take place. The section 34 is thus cooled. This also cools the cooling fluid as it passes through section 34 .

The section 34 can have a heat exchange element 36 with which the surface area of the section 34 can be increased. This increases the effective cross section of the cooling, since the heat exchange between the cooling gas flow 40 and the section 34 can take place over an enlarged surface.

The fluid line 32 preferably carries the cooling fluid from the cooling channel system 38 to the cooling device 20 and is then designed as a return line 54 .

However, this does not rule out the possibility that the fluid line 32 can conduct cooling fluid from the cooling device 20 to the cooling channel system 38 and can therefore be designed as a supply line 52 .

After the cooling gas flow 40 has been heated by the heat exchange with the section 34 of the fluid line 32 , the cooling gas flow 34 is collected in the dry air chamber 44 after passing through the through opening 60 .

In order to avoid heat exchange with the ambient air of the blow molding station 18, the collection chamber 42 can have a thermally insulated chamber wall 62.

The dry air chamber 44 has at least one dry air opening 56 for generating a curtain of dry air from the heated cooling gas stream. The dry air opening 56 generates a dry air flow from the inflowing heated cooling gas flow. The dry air stream is in shape a curtain of drying air directed at at least a portion of the outer surface of the tuyere 28. This prevents liquid from condensing on the blow mold 28 .

In order to avoid heat exchange with the ambient air of the blow molding station 18, the drying air chamber 44 can have a thermally insulated chamber wall 50.

All in all, the blown air flows when it is released from the blow mold 28 through the outlet opening 30 as a cooling gas flow 40 into the collection chamber 42 and then via the through-opening 60 around the section 34 of the fluid line 32 into the drying air chamber 44. The blown air escapes from the drying air chamber 44 as a curtain of drying air of the drying air opening 56 in the vicinity of the blow molding station 18 and sweeps around the blow mold 28.

The example described above is in no way intended to limit the invention. Rather, the invention can be modified in many ways. All features of the invention described above can be essential for the invention alone or in combination with one another.

reference list

10

Apparatus for blow molding containers

12

feeding device

14

transport wheel

16

heating section

18

blow station

20

cooler

22

Cooling fluid supply line

24

cooling fluid return line

26

blow wheel

28

blow mold

30

exhaust port

32

fluid line

34

section

36

heat exchanger element

38

cooling channel system

40

cooling gas flow

42

collection chamber

44

dry air chamber

46

silencer

48

rotary introduction

50

chamber wall

52

flow line

54

return line

56

dry air vent

58

alignment element

60

passage opening

62

chamber wall

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102017103438 A1 [0003]

Claims (9)

Device for blow molding containers from preforms made of thermoplastic material, the at least one blow station (18), the at least one blow mold (28) for shaping a thermally conditioned preform inserted into the blow mold (28) by means of blowing gas and at least one fluid-communicating with the blow mold (28 ) connected outlet opening (30) for expanding the blowing gas used in the blow mold (28), and at least one cooling device (20) for cooling the blowing station (18) by means of a cooling fluid, wherein the cooling device (20) comprises at least one fluid line (32) for the cooling fluid, which is fluidly connected to a cooling channel system (38) of the blow mold (28), characterized in that the outlet opening (30) is designed to generate a cooling gas flow (40) by means of the expanded blowing gas, at least one section (34 ) of the fluid line (32) is arranged in the cooling gas stream (40). device after claim 1 , characterized in that the at least one section (34) of the fluid line (32) has a heat exchanger element (36) which is arranged in the cooling gas flow (40). device after claim 1 or 2 , characterized in that the device (10) has a collection chamber (42) for collecting the expanded blowing gas with at least one passage opening (60) for the cooling gas stream (40), the outlet opening (30) being fluidly connected to the collection chamber (42). and the at least one section (34) of the fluid line (32) is arranged in the through-opening (60). device after claim 3 , characterized in that the device (10) has a drying air chamber (44) with at least one drying air opening (56) directed towards the blow mold for generating a curtain of drying air from the heated cooling gas stream (40), the drying air chamber (44) being in relation to the collecting chamber (42) is arranged downstream of the cooling gas flow (40) and is connected in fluid communication with the collection chamber (42) via the through-opening (60). device after claim 3 or 4 , characterized in that the device (10) has at least one chamber wall (50, 62) which is thermally insulated. Device according to one of Claims 1 until 5 , characterized in that the at least one fluid line (32) is a supply line (52) or a return line (54). Device according to one of Claims 1 until 6 , characterized in that a silencer (46) is arranged at the outlet opening (30) for dampening noise of the expanding blow gas. device after claim 7 , characterized in that the silencer (46) has an alignment element (58) for aligning the cooling gas flow (40) to the fluid line (32). Device according to one of Claims 1 until 8th , characterized in that the device (10) has a plurality of blow molding stations (28) which are each connected to the cooling device (20) in fluid communication via at least one fluid line (32).

Images